1. Field of the Invention
The present invention relates to a crawler crane and more particularly to a layout of a cabin and a power unit both mounted on an upper rotating body.
2. Description of Related Art
Generally, an upper rotating body of a crawler crane is provided, as a frame structure, with a rotating frame located centrally and extending along the longitudinal direction, and right and left deck frames mounted on right and left sides of the rotating frame respectively. An example of such a crawler crane is disclosed, for example, in Japanese Patent Laid-Open Publication No. 2005-314106 (US2007/0175849A1). In this example, a base end of a boom is supported pivotally at a front end of a rotating frame. Moreover, plural winches for winding wire ropes which are used for winding up or winding down lifting hooks suspended from a front end of the boom are disposed on the rotating frame longitudinally in a row in a plane view. Further, a cabin is usually disposed on one of the deck frames disposed on both sides of the rotating frame and a power unit comprising an engine and a hydraulic pump is disposed on the other deck frame. The power unit, which is also called a power plant or a power source, is disposed on the other deck frame longitudinally, namely, the longitudinal direction of the power unit is directed in the front and rear direction of the crawler crane.
In the case of such an upper rotating body, its width is determined by the sum of the width of the winches disposed on the rotating frame, the width of the cabin disposed on one deck frame, and the width of the power unit disposed on the other deck frame. For enhancing the easiness of workability or transportability when disassembling the crawler crane, and mounting/transporting the upper rotating body on a trailer, it is desired that the width of the upper rotating body be shortened as small as possible.
To meet such a requirement, it is proposed that both cabin and power unit, which are large in occupying width, be disposed on the front and rear portions of one and the same deck frame. An example of such a crawler crane is disclosed in Japanese Patent Laid-Open Publication No. 2000-136089 (U.S. Pat. No. 6,520,358 B1). In the case of this example, it is necessary that a soundproof material of a large mass be provided on a rear surface of the cabin lest sounds generated from a driving power section involving the engine and the hydraulic pump in the power unit should be propagated to the interior of the cabin through the rear surface of the cabin. However, using such an anti-sound measure causes the problem that the cost increases.